The purpose of the presently proposed experiments is to answer questions about the dynamics of auditory information processing and memory. Three experiments were designed to clarify the mechanisms underlying auditory backward recognition masking and auditory memory interference. Specifically, the effects of practice and the differential effects of interfering stimuli that differ in their similarity to the target stimuli will be examined. The results will be interpreted within the framework of a successive-stage information processing model and particular interest will be directed to estimating the duration of preperceptual storage. The experiments should help to clarify the mechanisms underlying normal perceptual abilities and this knowledge may be applied to the understanding and treatment of cases of abnormal perception.